DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)

DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)

DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)

DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)

DALLAS, TX - SEPTEMBER 14: Republican presidential candidate Donald Trump speaks during a campaign rally at the American Airlines Center on September 14, 2015 in Dallas, Texas. More than 20,000 tickets have been distributed for the event. (Photo by Tom Pennington/Getty Images)